Interventions
All the interventions considered in this review included modifying or restricting diet or increasing exercise, or both; however there was considerable variation in the interventions used, which included:
diet only (eight studies): low glycaemic load (GL) diet versus conventional healthy eating or routine or other care: Angel 2011; Clapp 2002a; Louie 2011; Moses 2009; Moses 2014; Rhodes 2010; ROLO 2012; one study evaluated a supervised low calorie diet (Magee 1990);
diet and exercise counselling (25 studies): Asbee 2009; Althuizen 2013; Bogaerts 2012; Dodd 2014; Ferrara 2011; Guelinckx 2010; Harrison 2013; Hawkins 2014; Huang 2011; Jackson 2011; Kieffer 2014; Korpi-Hyovalti 2011; Luoto 2011; Marcinkevage 2012; Mujsindi 2014; Petrella 2013; Phelan 2011; Pollak 2014; Polley 2002; Quinlivan 2011; Rauh 2013; Renault 2014; Szmeja 2011; Vesco 2013; Wilkinson 2012;
exercise interventions (e.g. supervised exercise, individualised exercise programs, dance classes, provision of pedometers or treadmills) (20 studies): Barakat 2011; Bisson 2014; Callaway 2010; Clapp 2002b; Cordero 2014; De Oliveria Melo 2012; Haakstad 2011; Kong 2014; Leiferman 2011; Murtezani 2014; Nascimento 2012; Oostdam 2012; Petrov Fieril 2014; Pinzon 2012; Poston 2013; Price 2012; Renault 2014; Ruiz 2013; Ronnberg 2014; Santos 2005;
diet and supervised exercise interventions (five studies): Hui 2006; Hui 2012; Hui 2014; Ruchat 2012; Vinter 2012;
diet counselling/other (seven studies): Di Carlo 2014; Jeffries 2009; Laitinen 2009; Rae 2000; Thornton 2009; Vitolo 2011; Wolff 2008.
Interventions varied in intensity. Control groups mostly comprised routine or standard care (which also varied considerably in different settings and was not always well-described). Hui 2006 compared a supervised group exercise and diet intervention with an exercise and diet information pack. Clapp 2002b compared different exercise intensities at different stages of pregnancy. Some studies included more than two arms (De Oliveria Melo 2012; Laitinen 2009; Guelinckx 2010; Renault 2014).